Process of smelting compounds and producing carbids.



Patented July 26, 1904.

UNITED STATESPATENT OFFICE.

WILLIAM SMITH IIORRY, OF NIAGARA FALLS, NEIV YORK, ASSIGNOR TO UNIONCARBIDE COMPANY, OF NIAGARA FALLS, NEIV YORK, A COR- PORATION OFVIRGINIA.

PROCESS OF SMELTING COMPOUNDS AND PRODUCING CARBlDS-Q SPECIFICATIONforming part of Letters Patent No. 765,838, dated July 26, 1904.

Application filed April 13,1904. Serial No. 203,239. (No specimens.)

To all whom it may concern.-

Be it known that I, WILLIAM SMITH HORRY, a citizen of the United States,residing at N iagara Falls, in the county of Niagara and State of NewYork, have invented certain new and useful Improvements in Processes ofSmelting Compounds and Producing Carbids, of which the following is aspecification.

Calcium carbid may be produced by heating a mixture of lime and carbonin an electric furnace employing either a direct or alternating current.In the original work of Thomas L. illson, at Spray, North Carolina, anelectric are produced by a direct current was employed. This inventorsubsequently obtained a patent for the production of carbid by the useof an alternating electric arc to wit, United States No. 541,137,reissued October 22, 1895, as No. 11,511. This patent states that acurrent which is reversed about fifty times a second is effective. Inthe commercial production of carbid at Niagara Falls, New York, acurrent having a frequency of twenty-live alternations per second hasbeen uniformly employed.

I have discovered that it is not only advantageous to employ analternating current for the production of carbid, but that the currenteflicioncy is a function of the current frequency. A frequency oftwenty-five per second is inferior to that of fifty per second describedin \Villsons specified patent, a frequency of one hundred and twentygives a much higher yield than one of fifty, and frequencies which areabove one hundred and thirty-three periods, and therefore greater thanthose given by any commercial machines, may be employed to still greateradvantage. I therefore propose to employ an alternating current of thehighest frequency which will not cause undue losses by inductive drop inthe current mains.

In carrying out the process the charge to be smelted-for example, amixture of finely-divided lime and carbonis fed into an electric furnaceof any approved type, such as the Horry furnace with a rotating body,and an alternating electric current having a frequency sufiiciently highto reduce the losses due to electrolytic decomposition to a practicableminimum is passed through the mixture, heating it to the requiredtemperature.

IVhile the increased production of calcium carbid due to the use of analternating current of abnormally-high frequency is a fact which I amnot fully able to account for by theoretical considerations, I am of theopin-' ion that the molten calcium carbid, as well as calcium oXid, actsas an electrolyte and that a direct current or an alternating current oflow frequency electrolytically decomposes both the carbid and oxid, aconsiderable portion of the electrical energy thus being bound in theproducts of electrolysis instead of being transformed into useful heat.A current of higher frequency liberates a smaller amount of ions at eachreversal, and the anions and cations liberated at the same electrode bythe successive current-waves of opposite direction may therefore beassumed to more fully recombine, their chemical energy being therebytransformed into heat of combination. The polarization electromotiveforce of an electrolyte is in many cases a function of the impressedelectromotive force and a quantity which has no definite InaXimum, andthe losses due to partial electrolysis in a calcium-carbid furnace usinga current of low frequency are serious on account of the high-potentialdifference maintained between the electrodes.

IVhile the process has been commercially utilized for the manufacture ofcalcium carbid, it is obviously useful for the production of othercarbids, silicides, &c., and in general for 'such smelting operations asare effected by heat generated by passing an electric current throughthe charge and in which electrolysis is undesirable.

I claim- 1. The process of smelting electrolyzable compounds, whichconsists in heating the charge by passing through it an alternatingelectric current having a frequency sufiicientl y high to substantiallyeliminate losses due to electrolytic decomposition, as set forth.

2. The process of smelting electrolyzable compounds, which consists inheating the charge by passing through it an alternating electric currenthaving a frequency of more than one hundred and thirty-three periods persecond, as set forth.

3. The process of smelting electrolyzable compounds, which consists inheating a mixture of the compound and a reducing agent by passingthrough the mixture an alternating electric current having a frequencysufficiently high to substantially eliminate losses due to electrolyticdecomposition, as set forth.

l. The process of smelting electrolyzable compounds, which consists inheating a mixture of the compound and a reducing agent by passingthrough the mixture an alternating electric current having a frequencyof more than one hundred and thirty-three periods per second, as setforth.

5. The process of producing calcium carbid,

WILLIAM SMITH HORRY.

Witnesses:

EUGENE A. BYRNES, CLINTON P. TOWNSEND.

